As the critical dimension of a semiconductor device continues to shrink, the thickness of a conventional gate dielectric layer including silicon dioxide cannot be reduced by conventional processes. Therefore, a high k (dielectric constant) insulating layer and a metal gate (HKMG) manufacturing process has been proposed.
After forming the metal gate, it is desirable that the contact resistance between a contact member of the metal gate and the metal gate is as small as possible. However, the contact resistance between the contact member and the metal gate of conventional devices is relatively large, and the resistance variations between different conventional devices are also relatively large.